Placental abnormalities

Placental Abnormalities

1. Placenta - Physiology and functionA. Fetus entirely dependent on placenta

until birth.B. Maternal and fetal blood kept separate by placental barrier.C. Protects the infant from infection and

harmful substances.D. Acts as endocrine organ - makes hormones to maintain pregnancy.E. Made of 12-20 cotyledons.F. Fetal blood transported to placenta via two umbilical arteries.

Placental Abnormalities (con’t)

G. Umbilical arteries get smaller and become arterioles then villi.

H. Villi suspended in pools of maternal blood in the lacunae. I. Fetal blood returns to fetus via umbilical vein.

Abruptio Placenta

1.Definition - Separation of the normally situated placenta from its uterine site of implantation after 20 weeks gestation, but before delivery of the placenta.

Abruptio Placenta (con’t)2. Placental Grades :

A. Grade 0 - Patient asymptomatic.Small retroperitoneal clot seen after delivery.

B. Grade 1 - Vaginal bleeding, may have abdominal tenderness or slight uterine tetany,mom and baby not in distress.

C. Grade 2 - Uterine tenderness, tetany with or without evidence of bleeding,

baby shows signs of distress.D. Grade 3 - Uterine tetany,severe bleed-

ing may not be visible. Baby is dead. Mom often has coagulopathy.

Abruptio Placenta

3. Incidence - Varies from 1-55 to 1-250 cases. Incidence greater with increasing parity or history of abruption.

Abruptio Placenta (con’t)

4. Etiology - Unknown. Possibly begins with degenerative changes in the small arterioles that supply the intervillous spaces, resulting in thrombosis, degeneration of the decidua, and finally rupture of the vessel. Then tearing and bleeding in the inner layer of the endometrium and decidua basalis. Hematoma forms along with retroperitoneal clot, compresses adjacent placenta, causing local destruction. Further bleeding causes increased pressure behind the placenta which causes further separation.

Abruptio Placenta (con’t)

5. Conditions associated with abruption:A. Hypertension - 5x higherB. TraumaC. Short umbilical cordD. PolyhydramniosE. IV cocaine useF. Uterine anomalies

Abruptio Placenta (con’t)

5. Conditions associated with abruption (con’t) :G. OB history

1. History of spontaneous abortions2. Premature labor3. Antepartum hemorrhage4. Stillbirth or neonatal death5. 6x greater with parity > 76. 30x greater with hx. of abruption7. Cigarette smoking - decidual

necrosis.

Abruptio Placenta (con’t)

6. S/S - Depends on type of abruptionA. Mild c/o labor pains, may only have

slight uterine irritability. May have no or only small amount of bleeding.

B. Severe knife-like pain with board-like abdomen. May/may not see bleeding. C. Uterus could be tender at point of separation or may be generalized over entire abdomen.

D. Increased uterine distention - elevated fundal height

Abruptio Placenta (con’t)

6. S/S - (con’t) - E. Bleeding may be minimal or diffuse.

Can be port-wine, dark, or bright red. F. Symptoms are determined by amount

of blood lost.G. Shock is severe.H. Fetal distress or death.

Abruptio placenta (con’t)

7. Diagnosis - A. Based on hx.,physical exam,lab values B. No analgesia/anesthesia until diagnosis

confirmedC.Vaginal bleeding with/without painD. Increased uterine tone, tendernessE. ShockF. Fetal distressG. U/S for placental localization,positionH. Palpation of abdomen, measure fundal

heightI. Confirm after delivery-inspect placenta.

Abruptio Placenta (con’t)

8. Maternal/ fetal outcome - mortality rate <1%, if undetected until fetal death, mortality rate is 10%

A. DIC - 30%B. Renal failure from hypovolemiaC. Amniotic fluid embolusD. Uterine ruptureE. Postpartum endometritisF. Postpartum hemorrhage

Abruptio Placenta (con’t)9. Medical management-

A. US to R/O placenta previa B. Bedrest (lateral position)

C. IV with large bore catheterD. Type and crossmatch, CBC, platelet

count, fibrinogen, bleeding timeE. Frequent vital signsF. Assess for signs of shock - cold,

clammy skin, pale, anxious, thirstyG. Assess FHR and uterine activityH. Mark top of fundus (check to see if rising

Abruptio Placenta (con’t)

9. Medical Management - (con’t)I. Observe for signs of vaginal bleedingJ.C/S for fetal distress, maternal blood

loss or compromise, coagulopathy, poor labor progress

K. Strict I & OL. Amniotomy to assess blood in fluidM. Oxygen per maskN. Avoid episiotomyO. Be aware of postpartum hemorrhage

Placenta Previa

1. Definition - Abnormally implanted placenta placed totally or partially in the lower segment of the uterus, rather than in the fundus. When the cervix begins to dilate and efface the placenta separates, allowing bleeding form the open vessels.

Placenta Previa (con’t)

2. Classifications -A. Complete - Internal os is completely

covered by the placenta.B. Partial - a portion of the cervical os

is covered by the placenta.C. Marginal - The edge of the placenta

extends to the edge of the cervical os.

Placenta Previa (con’t)

3. Incidence - Depends on which trimester pregnancy is in.

A. 2nd trimester - 45% in lower uterine segment

B. 3rd trimester - 0.5 to 1% in lower uterine segment

C. Occurs more often in multips - 80%D. History of previa - 12x more likelyE. More common with history of abortions

C/S, molar pregnancies, fibroids, uterine surgery.

Placenta Previa (con’t)

4. Etiology - unknown cause A. It is thought that when the embryo is

ready to implant and the decidua in the fundus is deficient, it will choose another spot lower in the uterine segment.

B. Placentas are larger on the maternal side, cord often has marginal or vellamen- tous insertion. Suggests that the placenta was growing toward more favorable decidua.

Placenta Previa (con’t)

4. Etiology - (con’t) -C. Endometriosis after previous pregnancy.D. Uterine scars - abortions, C/S, molar

pregnancyE. Tumors altering contour of uterus.F. Close pregnancy spacingG. MultiparityH. Large placenta- in multiple gestations or

erythroblastosis fetalisI. High altitudesJ. Male fetus

Placenta Previa (con’t)

1. Painless bright red vaginal bleeding - usually 1st bleeding episode not before 30 wks.2. Sometimes suspected with oblique or transverse lie.3. Diagnosed by U/S 4. 80-90% - bleeding occurs without warning5. Uterus non-tender - no rise in fundal height.6. Often occurs when sleeping7. 1st episode usually scant, each episode more8. Shock9. May deliver by C/S if placenta covers cervix

Placenta Previa (con’t)

1. Maternal and fetal outcome-A. Mortality less than 1%, morbidity 20%B. Most will have at least one significant

hemorrhage , 25% will go into shockC. Vaginal and cervical lacerations

occur more often with vaginal delivery.D. Poor endometrium may contribute to

placenta accreta.E. Fetal mortality 20% - prematurity,

hypoxia, developmental disorders.

Placenta Previa (con’t)

1. Medical Management - Depends on gestational age and severity of bleed.

A. Strict bedrestB. IV - large bore catheter (16 gauge)C. CBC, type & screen, platelet count,

fibrinogen, bleeding timeD. If HCT less than 30% transfuseE. No pelvic examsF. Adequate hydration, accurate I & O

Placenta Previa (con’t)

1. Medical Management - (con’t)G. Tocolysis for contractionsH. No douching or intercourseI. Oxygen per maskJ. Serial U/S to check for placental

placement, fluid level, fetal growth.K. C/S for large blood loss

Vasa Previa

Rare circumstance that may occur withvelamentous insertion of the cord where umbilical vessels cross the internal os presenting ahead of the fetus. Requires a C/S.

Velamentous Insertion of the Cord

1% singleton term births.

Vessels of cord separate a distance away the margin of the placenta surrounded only bya fold of amnion.

If bleeding is seen it should be tested for fetal Hgb - Kleihauer -Betke - fetus may become hypovolemic.

Placenta Accreta

1. Definition - a rare condition• all or part of placenta adherent

to the myometrium. • The normal spongy layer of decidua

is absent or defective, therefore placntal villi grows down through the endometrium into the myometrium2. Types -

A. Accreta - Villi extends too far into endometrium.

B. Increta - Villi invade into myometriumC. Percreta - Villi invade through

myometrium to the serosa layer.

Placenta Accreta (con’t)

3. Incidence - 1-70004. Predisposing factors -

A. Implantation over a previous C/S scar or other surgical scar in the uterine cavity.

B. Previous curretaggeC. Prior hx. Of endometritis or other

endometrial traumaD. High parityE. Placenta previa sometimes precludes

accreta

Placenta Accreta (con’t)5. S/S - None until delivery

A. Depends on depth, site of penetration, number of cotyledons involved.

B. If accreta is partial some cotyledons may separate from the uterine wall leaving open, bleeding vessels. The uterus is unable to contract because of the adherent placenta still within the uterine cavity. Profuse hemorrhage. C.If total accreta, tearing occurs when doctor tries to deliver placenta. Uterine inversion may occur.

Placenta Accreta - (con’t)

6. Diagnosis - Attempts to remove placenta reveals placental adherence.7. Outcome -

A. hemorrhageB. ShockC. HysterectomyD. Uterine inversion

Placenta Accreta (con’t)

8. Treatment - A. Large bore IV catheterB. IV fluids, bloodC. UltrasoundD. Type and Screen, CBC, platelet count,

fibrinogen, bleeding timeE. Accurate I & O F. Assess vital signsG. D & C / hysterectomy

Battledore Placenta

Cord inserted at or near the placental margin, rather than in the center.

Circumvellate Placenta

The fetal surface of the placenta is exposedthorough a ring of chorion and amnion openingaround the umbilical cord.

Succenturiate Placenta

One or more accessory lobes of the villi have developed. Vessels from the major to the minorlobes are only supported by membrane. Thisincreases the likelihood that the minor lobe(s) are may be retained during the third stage oflabor.

Couvelaire Uterus

Occurs in severe abruptio placenta when blood collects in the uterine musculature beneath the uterine serosa, into connective tissue of the broad ligaments and even into the peritonealcavity. Suturing followed by administration of IV oxytocin postpartally usually controls postpartum hemorrhage.